Loudspeaker modules are important acoustic component of portable electronic devices, for completing the conversion between an electric signal and an acoustic signal, and are energy conversion devices. The existing loudspeaker modules usually comprise a shell, wherein the shell accommodates a vibrating system and a magnetic circuit system. The vibrating system comprises a vibrating diaphragm and a voice coil which are combined together. A whole inner cavity of the module is divided by the vibrating diaphragm into two cavities, i.e. a front voice cavity and a rear voice cavity. F0 (resonant frequency) is an important index of loudspeaker modules, and as its value decreases, a loudspeaker module has a wider frequency band and a better acoustic performance. F0 is mainly influenced by the volume of the rear voice cavity and the compliance of the vibrating diaphragm in the module, i.e., the value of F0 is smaller as the volume of the rear voice cavity or the compliance of the vibrating diaphragm increases.
However, since portable electronic devices continuously become thinner, lighter and compacter, loudspeaker modules are also increasingly thinner and smaller, and thus the volume of the rear voice cavity is continuously decreased. As the volume of the rear voice cavity of loudspeaker modules is continuously decreased, an effective method for decreasing the F0 is to select a vibrating diaphragm of a large compliance. However, the vibrating diaphragm of a large compliance may be easily crimped, and the assembling is difficult. In order to reduce the difficulty in assembling of the vibrating diaphragm of a large compliance, a person skilled in the art will bond an annular metal ring as the supporting member at the edge portion of the vibrating diaphragm to prevent the vibrating diaphragm from being crimped. Although the annular supporting member effectively prevents the vibrating diaphragm from being crimped and reduces the difficulty in assembling, it occupies part of the space of the rear voice cavity, and the effective volume of the rear voice cavity is reduced. As a result, the F0 of the loudspeaker module increases and the acoustic performance of the loudspeaker module is degraded.